Psychogenic amnesia: syndromes, outcome, and patterns of retrograde amnesia

Abstract

There are very few case series of patients with acute psychogenic memory loss (also known as dissociative/functional amnesia), and still fewer studies of outcome, or comparisons with neurological memory-disordered patients. Consequently, the literature on psychogenic amnesia is somewhat fragmented and offers little prognostic value for individual patients. In the present study, we reviewed the case records and neuropsychological findings in 53 psychogenic amnesia cases (ratio of 3:1, males:females), in comparison with 21 consecutively recruited neurological memory-disordered patients and 14 healthy control subjects. In particular, we examined the pattern of retrograde amnesia on an assessment of autobiographical memory (the Autobiographical Memory Interview). We found that our patients with psychogenic memory loss fell into four distinct groups, which we categorized as: (i) fugue state; (ii) fugue-to-focal retrograde amnesia; (iii) psychogenic focal retrograde amnesia following a minor neurological episode; and (iv) patients with gaps in their memories. While neurological cases were characterized by relevant neurological symptoms, a history of a past head injury was actually more common in our psychogenic cases (P = 0.012), perhaps reflecting a 'learning episode' predisposing to later psychological amnesia. As anticipated, loss of the sense of personal identity was confined to the psychogenic group. However, clinical depression, family/relationship problems, financial/employment problems, and failure to recognize the family were also statistically more common in that group. The pattern of autobiographical memory loss differed between the psychogenic groups: fugue cases showed a severe and uniform loss of memories for both facts and events across all time periods, whereas the two focal retrograde amnesia groups showed a 'reversed' temporal gradient with relative sparing of recent memories. After 3-6 months, the fugue patients had improved to normal scores for facts and near-normal scores for events. By contrast, the two focal retrograde amnesia groups showed less improvement and continued to show a reversed temporal gradient. In conclusion, the outcome in psychogenic amnesia, particularly those characterized by fugue, is better than generally supposed. Findings are interpreted in terms of Markowitsch's and Kopelman's models of psychogenic amnesia, and with respect to Anderson's neuroimaging findings in memory inhibition.

Autobiographical memory in amnesia

“…The temporal patterns of the two FRA groups were virtually identical: both showed a recency effect with poor memory for facts from their childhood or early adulthood, but relative sparing of more recent memories. This is opposite to the pattern typically observed in Harrison et al's neurological patients [59], and in studies of transient global amnesia (compare also figure 1). At follow-up, the fugue group had improved to normal, scoring at the same level as controls.…”

“…A psychogenic fugue state can be defined as a sudden loss of memory, involving the loss of all autobiographical memories and the sense of personal identity [59]. This is usually associated with a period of wandering, and typically lasts for a few hours or days up to about 4 weeks.…”

“…Harrison et al [59] reviewed 53 cases seen by Prof Kopelman during the course of 20 years. These cases were classified into 4 sub-groups.…”

“…During a fugue state, the medial temporal system appears to be working normally, allowing the person to operate in his/her environment. However, this system cannot be functioning completely normally because, when people come out of a fugue, they have no memory for what they had been doing during the fugue episode (see also [59]).…”

Non-convulsive status epilepticus: mimics and chameleons

“…Psychogenic amnesia, lasting hours to days, can present with fugue states, loss of autobiographical information and failure to recognise family. In further distinction to transient global amnesia, they have profound retrograde but mild anterograde amnesia, and a history of stressful life events and depression 76. ‘Transient epileptic amnesia’ usually lasts 30 min and occurs on wakening in adults in their 50s.…”